This invention relates to television receiver assembly and construction.
Typically a television receiver may include a cabinet housing a CRT display device and a metal chassis supporting a plurality of printed circuit modules containing receiver signal processing and display producing circuitry. Electrical connections are made between the modules, the CRT display device and the remainder of the receiver circuitry by either permanent solder connections or mechanical connector assemblies. A cabinet back, affixed to the rear portion of the cabinet, completes the cabinet enclosure.
In some television manufacturing operations, generally those of smaller volume, the receiver chassis, printed circuit modules, electrical interconnections and supporting cabinet are manufactured and assembled at one location. More often, however, television manufacturing operations are dispersed among a number of "feeder" plants, each of which may specialize in the production of a portion of a receiver. For example, the printed circuit modules may be assembled at one plant, the metal chassis frame fabricated at another, the cabinet at a third, etc., with the output of each plant shipped to still another for assembly, alignment, testing and packaging of the receiver. It is also common to further divide manufacturing facilities and utilize a number of plants to produce subassemblies for other plants in the system. Whenever the manufacture of the printed circuit modules takes place at a remote location, they obviously must be packaged for transportation and/or storage. During chassis assembly the modules are unpacked, mounted to the metal chassis and electrically connected.
Although the shape, size and number of printed circuit modules used vary with individual manufacturer preferences, their basic construction is similar. An insulating board or substrate has metalized connection pattern, typically formed by a photoetching process, on at least one surface and a plurality of circuit components supported on the other surface, each component having lead connections which pass through holes in the board for soldering at appropriate points on the metalized pattern. The circuit components are themselves of differing configurations and sizes giving the completed module an irregular volumetric shape which makes storage difficult and exposes those components which extend farthest from the board to risk of damage during handling and storage.
Because of this irregular configuration and the fragile nature of the printed board and the components thereon, specifically designed transporting carriers are generally employed to transport and store the modules in multi-plant manufacturing operations. In a typical construction, cardboard or similar material forms a multi-celled container which accommodates the printed circuit modules. The completed modules are placed within the container (generally one per cell) and stored or shipped. During assembly the modules are removed from the container and the now-empty-container is returned to the module source. One can readily see that expenses associated with such packing and unpacking operations as well as those associated with return shipment of empty containers can constitute significant expense.
The fragile nature of the printed circuit modules also entails risk of damage when the modules are assembled on the chassis, especially if fasteners are used. Sometimes mechanical stresses may damage the printed circuit board, creating defects which are not detectable by testing. Such latent defects may only become a problem after hours of repeated temperature cycling inherent in normal operation of the receiver.
In addition to the above problems of module transportation and storage, a television receiver of the type described may not be readily serviceable in the field. For example, if the receiver modules are permanently affixed to the chassis by solder connections, module accessibility is limited and servicing may require that the entire chassis be removed to a remote servicing location notwithstanding that only a single module may be in need of repair. Some improvement in this aspect of serviceability is realized by some recent receivers which incorporate removable modules having electrical connections made by connectors.
Here again, removal of the modules from the protective environment of the receiver for servicing entails a risk of damage during transportation. Some television service organizations use module transporting carriers, similar to those used in the factory, to minimize this risk. This, of course, requires additional expense and space.